Added functions for list write and sort operations

core-kotlin-modules/core-kotlin-collections/src/main/kotlin/com/baeldung/collections/ListExample.kt

@@ -84,5 +84,99 @@ class ListExample {
         return countries.firstOrNull { it.length > 8 }
     }
 
-    //5. Retrieve parts of the list
+    fun retrieveSubList(): List<String> {
+        val subList = countries.subList(1, 4)
+        println(subList)
+        return subList
+    }
+
+    fun retrieveListSliceUsingIndices(): List<String> {
+        val sliceList = countries.slice(1..4)
+        println(sliceList)
+        return sliceList
+    }
+
+    fun retrieveListSliceUsingIndicesList(): List<String> {
+        val sliceList = countries.slice(listOf(1, 4))
+        println(sliceList)
+        return sliceList
+    }
+
+    fun countList(): Int {
+        val count = countries.count()
+        println(count)
+        return count
+    }
+
+    fun countListUsingPredicate(): Int {
+        val count = countries.count { it.length > 5 }
+        println(count)
+        return count
+    }
+
+    fun countListUsingProperty(): Int {
+        val size = countries.size
+        println(size)
+        return size
+    }
+
+    fun addToList(): List<String> {
+        cities.add("Barcelona")
+        println(cities)
+        cities.add(3, "London")
+        println(cities)
+        cities.addAll(listOf("Singapore", "Moscow"))
+        println(cities)
+        cities.addAll(2, listOf("Prague", "Amsterdam"))
+        println(cities)
+        return cities
+    }
+
+    fun removeFromList(): List<String> {
+        cities.remove("Seoul")
+        println(cities)
+        cities.removeAt(1)
+        println(cities)
+        return cities
+    }
+
+    fun replaceFromList(): List<String> {
+        cities.set(3, "Prague")
+        println(cities)
+        cities[4] = "Moscow"
+        println(cities)
+        cities.fill("Barcelona")
+        println(cities)
+        return cities
+    }
+
+    fun sortMutableList(): List<String> {
+        cities.sort()
+        println(cities)
+        cities.sortDescending()
+        println(cities)
+        return cities
+    }
+
+    fun sortList(): List<String> {
+        val sortedCountries = countries.sorted()
+        println("countries = $countries")
+        println("sortedCountries = $sortedCountries")
+        val sortedCountriesDescending = countries.sortedDescending()
+        println("countries = $countries")
+        println("sortedCountriesDescending = $sortedCountriesDescending")
+        return sortedCountriesDescending
+    }
+
+    fun checkOneElementInList(): Boolean {
+        return countries.contains("Germany")
+    }
+
+    fun checkOneElementInListUsingOperator(): Boolean {
+        return "Spain" in countries
+    }
+
+    fun checkElementsInList(): Boolean {
+        return cities.containsAll(listOf("Calcutta", "Sao Paulo", "Sydney"))
+    }
 }

core-kotlin-modules/core-kotlin-collections/src/test/kotlin/com/baeldung/collections/ListExampleUnitTest.kt

@@ -3,6 +3,7 @@ package com.baeldung.collections
 import org.junit.jupiter.api.Test
 import org.junit.jupiter.api.Assertions.assertEquals
 import org.junit.jupiter.api.Assertions.assertNotEquals
+import kotlin.test.assertFalse
 import kotlin.test.assertNull
 import kotlin.test.assertTrue
 
@@ -30,4 +31,78 @@ class ListExampleUnitTest {
     fun whenRetrieveElementsFirstAndLast_thenSuccess() {
         assertEquals("Australia", classUnderTest.retrieveElementsFirstAndLast())
     }
+
+    @Test
+    fun whenRetrieveSubList_thenSuccess() {
+        assertEquals(3, classUnderTest.retrieveSubList().size)
+    }
+
+    @Test
+    fun whenRetrieveListSliceUsingIndices_thenSuccess() {
+        assertEquals(4, classUnderTest.retrieveListSliceUsingIndices().size)
+    }
+
+    @Test
+    fun whenRetrieveListSliceUsingIndicesList_thenSuccess() {
+        assertEquals(2, classUnderTest.retrieveListSliceUsingIndicesList().size)
+    }
+
+    @Test
+    fun whenCountList_thenSuccess() {
+        assertEquals(5, classUnderTest.countList())
+    }
+
+    @Test
+    fun whenCountListUsingPredicate_thenSuccess() {
+        assertEquals(3, classUnderTest.countListUsingPredicate())
+    }
+
+    @Test
+    fun whenCountListUsingProperty_thenSuccess() {
+        assertEquals(5, classUnderTest.countListUsingProperty())
+    }
+
+    @Test
+    fun whenAddToList_thenSuccess() {
+        assertEquals(11, classUnderTest.addToList().count())
+    }
+
+    @Test
+    fun whenRemoveFromList_thenSuccess() {
+        val list = classUnderTest.removeFromList()
+        assertEquals(3, list.size)
+        assertEquals("Sao Paulo", list[1])
+    }
+
+    @Test
+    fun whenReplaceFromList_thenSuccess() {
+        val list = classUnderTest.replaceFromList()
+        assertEquals(5, list.size)
+        assertEquals("Barcelona", list[1])
+    }
+
+    @Test
+    fun whenSortMutableList_thenSuccess() {
+        assertEquals("Sydney", classUnderTest.sortMutableList()[0])
+    }
+
+    @Test
+    fun whenSortList_thenSuccess() {
+        assertEquals("India", classUnderTest.sortList()[1])
+    }
+
+    @Test
+    fun whenCheckOneElementInList_thenSuccess() {
+        assertTrue(classUnderTest.checkOneElementInList())
+    }
+
+    @Test
+    fun whenCheckOneElementInListUsingOperator_thenSuccess() {
+        assertFalse(classUnderTest.checkOneElementInListUsingOperator())
+    }
+
+    @Test
+    fun whenCheckElementsInList_thenSuccess() {
+        assertTrue(classUnderTest.checkElementsInList())
+    }
 }